The main objective of the study was an attempt to obtain a
general explanation for the geographical pattern of agricultural income.
This was undertaken in the belief that certain possible determinants
of agricultural income, specifically those related to natural
resource characteristics, have not been satisfactorily considered in
investigations up to...
Three different approaches to type checking have been taken in object-oriented programming languages. Smalltalk-80 uses run-time type checking. C++ uses subtypes. A third alternative is to use parameterized types. We examine the difficulties of programming in an object-oriented fashion with compile-time type checking and argue that parameterized types are better...
Using Smalltalk-80, programmers can produce prototypes much faster than with C or Pascal. What techniques do Smalltalk-80 programmers use to produce these prototypes? What is special about Smalltalk-80 that enables them to uses these techniques? Can these techniques be used with conventional languages such as C? In an attempt to...
Several years ago we began development of an object-based programming language and environment which we call X2. We implemented X2 using a virtual machine similar to Smalltalk-80 implementations, but X2 does no message look-up. The implementation differs from most Smalltalk-80 systems in that objects are paged and in the ability...
The term object-oriented is defined. This definition is then related to message-passing, inheritance, polymorphism, data abstraction, generics, and overloading.
Smalltalk-80 obtains some of its expressive power from arranging classes in a hierarchy. Inheritance is an important aspect of this hierarchy. An alternative organization of classes is proposed that emphasizes description instead of inheritance. This alternative can be used with compile-time type checking and retains the important characteristics of Smalltalk's...
